Backyard bug-watchers are seeing the winged bugs known as cicadas come out of their holes in New Jersey and North Carolina after 17 years of underground slumber — and scientists say a full-scale outbreak may not be far behind.

"There are some pretty convincing reports coming out," John Cooley, an expert on cicadas at the University of Connecticut, told NBC News. "It's fair to say it's starting, but it's still in the very early stages. It certainly isn't going all crazy. ... When it really happens, it's not going to be like this. It's going to be shovel loads of cicadas."

Cooley maintains one of the most closely watched websites for this spring's emergence, Magicicada.org. Little bug logos are popping up on different areas of Magicicada's interactive map, which means a smattering of Internet users are seeing cicadas coming out of the ground. In some cases, they're even seeing the bugs crawling around as adults.

Cooley, however, says that we ain't seen nothing yet. "When it really happens, we expect that website will just light up," he said.

The outlook is similar on other bug-watching sites — such as Radiolab's Cicada Tracker, which is encouraging listeners to put out their own soil-thermometer setups. Those readings are considered key leading indicators for cicada activity, because researchers have found that the bugs emerge en masse when the springtime soil temperature reaches 64 degrees Fahrenheit (18 degrees Celsius). A different temperature tracker set up by the Sutron information network for the Washington area suggests that the nation's capital still has a way to go before the cicadas come out.

Insects are expected to emerge by the billions on the East Coast, across an area stretching from North Carolina to Connecticut. This army of bugs, known as Brood II, spends 17 years feeding on plant roots underground. Sometime between late April and early June, depending on the weather, the insects burrow out of the ground as nymphs. The juveniles shed their outer skins, crawl up trees or buildings, and fly around to find their mates. The females lay their eggs, and then the adults die in droves. All this happens in the course of four to six weeks.

After another few weeks, a new generation of nymphs hatch from the eggs, drop to the ground, burrow into the soil and begin the next 17-year cycle.

Red-eyed cicadas cluster on leaves in Annandale, VA., during the Brood X emergence of 2004. Like Brood II, Brood X comes out every 17 years - but the timing of the cycle is different.

Brood II is just one of several broods of 13-year and 17-year periodical cicadas: The last big bug outbreak featured Brood XIX, which created a huge buzz in Southern states in 2011. This year's emergence is expected to begin in the South as well, though that's not guaranteed.

"Our expectation has been that we would hear from folks in North Carolina first," said Missy Henriksen, vice president of public affairs for the National Pest Management Association. However, the only cicada sighting she's actually been able to confirm was made in New Jersey. Although the insects tend to swarm in rural or suburban areas, there's a chance they could be sighted in urban enclaves such as New York's Central Park or the Bronx Zoo as well.

Cooley said he expected the pace of sightings to accelerate in the days ahead. "Within a week or so, it ought to really be going," he told NBC News. "Spring can't hold off forever."

When it comes, a cicada emergence can fill the skies with flying bugs, and fill the ears with a hum as loud as a jet engine or lawn mower. Those who have been through the full-frontal buzz say the experience can be disconcerting if you're not prepared for it. But cicadas are not considered a threat to humans. In fact, they can be quite delicious.

For true bug fans, the best response to the emergence is to lie back and enjoy it. "I'm looking forward to it," said Cornell University entomologist Cole Gilbert, who's expecting to catch the trailing edge of the Brood II outbreak in upstate New York. "I think it's pretty cool."

Thanks to the rapid rise of crowdsourcing and social media, this year's event is sure to become the most tweeted cicada emergence in history: Cicada Mania suggests using the hashtag #BroodII for the 2013 outbreak, and #Cicadas for general cicada issues. If you want to see the Twitterverse from the cicadas' point of view, just follow @Brood_II. There's a Cicada Mania Facebook page for entomophiles. And if you're an entomophobe, you'll find kindred spirits on the "I Hate Cicadas!!!!!!" Facebook page.